Magnetic ore-separator



A F JOBKE MAGNETIC ORE SEPARATOR.

APPLICATION FILED APR.24,1918. 1,346,544. Patented July 13, 1920.

INV EN TOR.

AUGUST F. JOBKE, 0F PITTSBURGH, PENNSYLVANIA.

MAGNETIC ORE-SEPARATOB.

Specification of Letters Patent.

Patented July 13, 1920.

Application filed April 24, 1918. Serial No. 230,604.

To all whom it may concern:

Be it known that 1, AUGUST F. Joann, a citizen of the United States, residing at Pittsburgh, in the county of Allegheny and State of Pennsylvania, have invented certain new and useful Improvements in TV agnetic Ore-separators, of which the followin is a specification. I

35y invention relates to improvements in magnetic separators and particularly the active magnetic fields thereof, and its objects are:

l. The increase in workingcapacity of a separator.

2. The formation of graded zones in a field formed by two opposing poles of an electromagnetic system.

3. The prevention of eddy currents in a moving separating member owing to its passage through a magnetic field.

4:. The avoidance of the sticking of ore particles to the separating member after its leaving a magnetic field, due to remanent magnetism.

In a preferred form of magnetic separa' tor, owing to the efiiciency of the arrangement, especially where a high intensity is aimed at, a magnetic member is provided with a wedge shaped edge opposite a magnet pole, to collect the ore particles and carry them out of the field. length of such an edge at a certain speed is the measure of the capacity of the separator. If a ring-shaped member, rotating about its axis, is provided with an edge, its length is limited to a certain dimension, and I therefore provide members arranged with their edges radially and in close proximity to each other, though separated from each other by air-spaces. Since their length can be made considerable with a corresponding extension of the magnet-poles, a relatively large capacity can be obtained.

The separating member, being with its separating edge arranged radially to a vertical. axis and normal to the direction of its motion, the flow of ore will also be radial and in the direction of the edge. Zones of varying strengths must be provided in a direction at a right angle to and increasing in strength in the direction of the flow of ore and are therefore to be arranged so as to The total.

divide the separating member into several parts belonging to the different zones.

To attain a gradual or Zonal variation of field strength at the edge of the separating member, it will be passed through a magnetic field of varying gap-length, since with a larger gap the field is weakened and with a shorter gap it will be strengthened, in other words, the relative reluctance of the field path determines the flux density in the separating member. Arranging the field strength so, that the ore entering the field first meets the weakest part of the same, permits taking out the magnetic particles ac" cording to their permeability, and therefore a classification of the components of the ore is accomplished.

A metallic body, such as the separating member, in passing through a magnetic field, produces eddy-currents, which depend not only upon the field strength and the speed with which it traverses the field, but also upon the linear dimensions of the same. Since the field strength, speed and length of the working edge of the separating member are the factors which determine the capacity of the separator, they are preferably not reduced, and I have found, that reducing the separating member in one or both dimensions normal to the working edge is effective in increasing the electrical resistance to eddy-currents that will arise, preterably the dimension in the direction of the motion. F or the other dimension, which is in the direction or" the magnetic flux, a certain length is essential, to enable a satisfactory flux-density or saturation in the separating member to be reached.

I have found, that, if a magnetic body, such as an iron strip is magnetized in a field across the flat, 2'. 6., its second smallest dimension, and particles are made to cling to its edges as the magnet-poles, a repellent action. takes place upon the reversal of the strip in the field, so that the flux through it isreversed. It is immaterial, whether the reversal is accomplished through the rotating of the strip or of the fielditself. The arrangement, which I shall describe, takes advantage of this discovery through the employment oi? a suitable separating member in conjunction with successive fields of alternately reversed direction, providing a stray flux of the quality described.

In describing my invention, reference may be had to the accompanying drawing, which shows several preferred formsof the same. In all views similar reference characters denote similar parts. z I

Figure l is a sectional view showing a magnetic field formed by an upper and lower magnet-pole with an air gap of varying length and traversed by a separating'member rotating about a vertical axis and normally to the direction of the flux. Fig. 2 shows a fractional plane view of a spider carrying a determined number of separating members. Fig 3 shows a similar view having the separating members slightly curved.- Figs. l and 5 are two sectional views of the separating members being adapted to vary the form of the field to suit varying requirements. Fig. 6 is a sectional view of the field formed byupper and lower magnet poles and a separating member, the arrangement providing for a distinctseparation of the magnetic field into three zones of difiierent strengths, and Fig. 7 is a sectional view similar to Fig. 6, but attaining the formation of distinct zones in a different way.

The pole 1 of an electromagnet with the winding 3 forms with the pole 2 above and separated from it by an air-gap a magnetic field of a substantially vertical direction. A conveyer at is providedto pass the ore to be treated through the field. The movable members 5, ino'unted 'on'a spider 6, which rotates about avertical axis, traverse the magnetic field normally to the direotion, in'

which the ore on the conveyerd travels. lhe relative velocities of the ore and the members 5 are arranged so that each particle at a certain moment is opposite and below the lower edge of one of the moving members andthe r'efore subject to the magneticattraction, which results from the magnetic flux being converged from the face of the lower pole to the edge. To make this co ncidence more certain the members 5 may be arranged at a certain small angle with the radial direction, as shown in Fig. 2, or they may be curved as shown in Fig. 3. According to the direction in which the rotating members 5 travel, the individual edge of a member may be kept over the same particle v for longer time. than in most magnetic separators, to enable the particle to even tually move itself free from entangling matter, "hus securing a more perfect separation; r

The field in ually converging one, and the lower edge of the members 5 is arranged parallel withtheconveyer. This'willprovide for a substantially similar form of field below each part of the edge except as to flux density and Fig. 1 is shown as a grad therefore for a gradually increasing attraction toward the inner end of the edge.

In Figs. 6 and 7 I have provided for zones of uniform but distinctly different values in the same field, in order to be enabled to separate materials of different permeabilities from one another, the variation in strength being greater than in other known arrangements. In Fig. 6 l attain this object by providing air-gaps of different lengths on both the upper and lower pole in stepping off the pole shoes 7 and 8. The flux density through the members 5 then varies accordingto the reluctance of the circuit through the dilferent air-gaps. In Fig.7 the same. object is attained with gaps of equal lengths by providing separate members 9 and '10 which are energized through the straying flux between poles 1 and 2. The principle of a similar arrangement is described in U. S. Patent 1,132,016 and is cited here to show the applicability of myinvention.

In Fig. l the members 5 are shown as being cast with one end into the non-magnetic spider 6. The other ends must then be free and insulated by an air-space from on'e'another to avoid the occurrence of inductive currents, the direction oiwiich would be radially along the members: 'SIHCG these currents would produce a"certain torq-ue with the field, there would be a serious amount of power required to move the mem-.

shapes provides a sharp edge at the lower end in order to concentrate the magnetic flux at it, and a fiat surface at the top in order to reduce the reluctance by providing a wider flux path through the air. Notches cut in the edge of the members 5, as shown in Figs. 6 and 7 facilitate the formation of uniform zones of different strengths and distinct segregation.

In Figs. 6 and 7 the members 5 are clamped by means of screws or bolts to the spider 6 and insulating material 11 is provided to prevent electrical contact. While in dry separation the use of insulation at this point is not essential, it will be found advantageous'as soon aS'wet separation isattempted,'since its thickness is the measure of a resistance in the circuit of. galvanic currents which may arise between'the iron members 5 and the non-magnetic alloy of spider 6.

Having thus described my invention, what member between upper and lower magnetpoles, having its largest dimension and a lower collecting-edge in the direction of the flow of ore and its smallest in the direction of its movement at right angle thereto and to the flow oi flux.

2. In a magnetic separator a separating member between upper and lower magnetpoles, having its largest dimension and a lower wedge-shaped edge in the direction of the flow of ore and its smallest in the direction of its movement at right angle thereto and to the flow of flux.

3. In a magnetic separator a separating member between upper and lower magnet poles, having its largest dimension and a lower collecting-edge in the direction of the flow of ore and a radius to a vertical axis, and its smallest in the direction of its movement at right angle thereto and to the flow of flux.

4. In a magetic separator a separating member between upper and lower magnetpoles, and in closer proximity to the upper pole, having its largest dimension and a lower collecting edge in the direction of the flow of ore and a radius to a vertical axis and its smallest in the direction of its movement at right angle thereto and to the flow of flux, and a conveyer between the lower pole and the separating member, parallel to the latter.

5. In a magnetic separator a separating member between upper and lower magnetpoles and in closer proximity to the former having its largest dimension and a lower collecting-edge in the direction of the flow of ore and being with one end connected radially to a spider rotating on a vertical axis, the other end being isolated from another separating member mounted on the same spider, and its smallest dimension in the direction of its movement at right angle to the flow of ore and of the flux, and a conveyer between the lower pole and the separating member, parallel to the latter.

6. In a magnetic separator a separating member having its largest dimension and a lower collecting edge in the direction of the flow of ore and traveling in a direction at a right angle thereto and in the direction of its smallest dimension across a magnet-field increasing in strength in the direction of the ore-flow.

7. In a magnetic separator a magnet-field of increasing strength in the direction of the flow of the ore formed by an upper and lower pole with a corresponding decrease of reluctance in the air-gap whose major portion is equally distributed above and below, a separating member, in closer proximity to the upper pole, having its largest dimension and a lower collecting-edge extending therethrough in the direction of the flow of ore and its smallest in the direction of its movement at right angle thereto and to the flow of flux, and a conveyer between the lower pole and the separating member, parallel to the latter.

8. In a magnetic separator a magnet-field formed by an upper and lower pole, both of which are stepped oil abruptly to form zonal gaps of uniform but increasing reluctance opposite to the direction of the flow of ore, a separating member, in closer proximity to the upper pole at the strongest zone, extending with its largest dimension and a lower collecting edge through the field in the direction of the flow of ore and having its smallest dimension in the direction of its movement at right angle thereto and to the flow of flux,

9. In a magnetic separator a magnet-field formed by an upper and lower pole, both of which are stepped ofl abruptly to form zonal gaps of uniform, but increasing reluctance, opposite to the direction of the flow of ore, a separating member, in closer proximity to the upper pole at the strongest zone, extending with its largest dimension and a lower collecting edge through the field in the direction of a radius to the vertical axis of a carrying spider and of the flow oi ore and having its smallest dimension in the direction of its movement at right angle thereto and to the flow of flux, and a conveyer between the lower pole and the separating member, parallel with the latter.

10. In a magnetic separator a magnetic field formed by an upper and lower pole with parallel faces stepped off abruptly in a direction opposite to the flow of flux, and a magnetic separating member extending parallel to and acrossthese faces, forming varying but uniform zones at its lower side.

11. In a magnetic separator a separating member, extending with its largest dimen sion and a lower separating edge in the direction of the flow of ore and at right angle to a magnet-field with zones of uniform but abruptly varying strength in the same direction, with notches in the lower collecting edge at the junction of zones, to segregate the edge into sections with varying but uniform attracting forces.

12. In a-magnetic separator a separating member, extending with its largest dimension and a lower collecting edge in the direction of the flow of ore and at right angle to the direction of its movement and to the low of flux, mounted with one end upon a spider, rotatable about a vertical axis, entirely insulated electrically from the spider and another separating member.

13. In a magnetic separator substantially vertical magnet-fields of alternately opposite directions formed by upper and lower poles located on a circle, having zonal. airgaps of uniform but increased strength, due to decreased reluctance in the circuits through the severaii zones toward the exile tion to a spider supporting one end of the of the said circle and in the direction ofthe said members and rotating about the said 10 flow of ore, electrically insulated separating axis, normal to the How of ore and the mag: members, in closer proximity to the upper netic flux, and a conveyer between the lower 7 poles, extending With their lmrgestdi-menpoles andtheseparating. members, parallel sion and :1, lower collecting edge, divided by With'th'e latter. i i V notch-es into sectlons corresponding to the ln testimony whereof I affix my signature; 15 said zones, in a substantially radlal' direc- AUGUST F; JOBKE. 

